Aegialoalaimidae Lorenzen, 1981

Leduc, Daniel, 2023, New nematode species and genera (Nematoda: Chromadorea) from cold seeps on Hikurangi Margin, New Zealand, European Journal of Taxonomy 856, pp. 1-45 : 28-29

Family incertae sedis Aegialoalaimidae Lorenzen, 1981

Diagnosis (emended from Holovachov 2015)

Cuticle smooth or finely annulated. Lateral alae absent. Epidermal glands absent. Somatic sensilla present. Labial region rounded, continuous with body contour. Inner labial sensilla indistinct. Outer labial sensilla pore-like or papilliform, located on outer surface of lips. Cephalic sensilla papilliform or setiform, located at base of labial region, anterior to amphid. Amphidial aperture circular. Subcephalic and cervical sensilla, deirid and ocelli absent. Secretory-excretory system present; renette cell located opposite to ventral side of pharynx, cardia or anterior part of intestine. Excretory ampulla present. Excretory duct very short, usually opens near level of nerve ring in males and further anteriorly in females. Stoma small, undifferentiated. Pharynx divided into anterior long tubular section with strongly cuticularised lumen and weakly developed tissue, and strongly muscularized oval basal bulb. Cardia cylindrical or conoid, partly enveloped by intestinal tissue in its posterior part. Female reproductive system didelphic, amphidelphic, ovary branches reflexed antidromously. Spermatheca present, axial. Vulva equatorial, transverse. Vagina thick; pars refringens vaginae absent. Male reproductive system diorchic, both testes outstretched. Spicules symmetrical, straight or arcuate; gubernaculum present or absent. Copulatory apparatus composed of a row of midventral precloacal sensilla (absent in some species). Postcloacal sensilla absent. Tail similar between sexes, conoid or subcylindrical with rounded terminus. Three caudal glands present, with common or multiple openings.

Remarks

This family was placed within the order Plectida by De Ley & Blaxter (2004) but was later considered incertae sedis by Holovachov (2014) due to lack of molecular data and unclear phylogenetic affinities. The placement of this family remains uncertain despite recent molecular analyses ( Leduc & Zhao 2021).